Plate-clamping device for printing-presses.



No. 695,4!4. Patented Mar. n, I902.

. y T. m. NORTH.

PLATE BLAMPINE DEVICE FOR PRINTING PBESSES.

(Application filed Feb. 21', 1901.) (In Model.)

m.- s95,4|4. Patented Mar. 11, I902.

T. :4. NORTH. PLATE CLAMPING DEVICE FOR PRINTING PBESSES.

(Application filed Feb. 21, 19 1.)

'(No Model.) 2Sheats-Sheet 2.

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ATENT Enron.

THOMAS M. NORTH, OF PLAINFIELD, NEW JERSEY, AssIeNOR'TO THE ALUMINUM PLATE AND PRESS COMPANY, OF PLAINFIELD,NEW JER- SEY, AND NEW YORK, Y., A CORPORATION OF wns'r VIRGINIA.

PLATE-CLAMPING DEVICE FOR PRlNTlN G-PRESSES.

SPEGIFIGA'IIONforming part of Letters Patent No. 695,41}, dated March 11, 1902. Application filed February 21, 1901. Serial No. 48,864. (No model.)

T0 (4% whom it may concern: 7

Be it known that I," THOMAS M. NORTH, a subject of the King of Great Britain and Ireland, residing at Plainfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Plate-Clamping Devices for Printing Presses, of which the following is a specification.

My invention relates to improvements in sheet-clamping devices for printing-cylinders of printing-presses -by which a sheet-metal printing-plate of aluminium, zinc, or other metal is secured in proper position upon the printing-cylinder. Many devices of this kind have been produced, butwith all such devices known to me the structureshave been such that the edges of the printing-plate have to be pulled inwardly (and are more or less bent) over the edges of the plate-supporting surface of the cylinder by the action of the clamps, which renders it dificult to exert a suflicient pull upon the different sections of a plate to equally strain it throughout its area, and when the plate is properly stretched or strained it is frequently broken :or injured along the bent edges. The old forms of platesecuring devices are also objectionable, because they require too much of the cylindersurface to be cut away for their-reception.

The Object of my present invention is to provide a simple andefiective plate straining and clamping device for printing-cylinders which will Overcome the di'fliculties pointed out. To this end I provide the printing-cylinder of a press with sectional'plate clamping and straining rolls supported in suitable sockets at the edges of the plate-supporting surface of the cylinder andprovided with means for engaging the edges of a printing-plate and with means for rotating the roll-sections in theirsupport for properly straining the plate. These improved plate straining and clamping devices roll the edges of the printing-plate upon them without abruptly bending or deflecting it and without any tendency to break or otherwise injure the printing-plate. The construction is such that a minimum portion of the printing-cylinder is cut away, thereby leaving a larger part of the cylinder-surface for the plate-receiving and ink-distributing surfaces. l

In order that my invention may be fully understood, I-will first describe the same with reference to the accompanying drawings and afterward pointout the novelty with more particularity in the annexed claims.

In said drawings, Figure 1 is a detail front elevation of ."part of a printing cylinder equipped with my improved plate straining and clamping devices. Fig. 2 is a transverse sectional view of the same, taken on the line 2 2 of Fig. 1. Figs. 3, 4, 5, and 6 are enlarged detail sectional views of a part of a printingcylinder, showing the improved plate straining and clamping devices, said views being taken on the section-lines 3 "3, 4: 4., 5 5, and 6 6, respectively, 'of Fig. 1' and the plateclamping roll being omitted in Fig. 6.

1 is aprinting cylinder of a printing-press having a plate-supporting surface 2 and an ink-distributing surface 3, said surfaces 2 and 3 being separated by longitudinally-extending gaps or cavities in which are mounted the plate strainingand clamping devices. The edges of the plate-supporting surface 2 are beveled or rounded off, as shown at 4, to avoid abrupt edges for'the printing-plate to be socured over. I

Directly beneath the front and rear edges of the plate-supporting surface 2 are formed the cylindrical sockets 5, out out at one side, as shown at 6. These sockets 5 are adapted to receive and support the sections of the plate straining and clamping rolls'7, which are of cylindrical form of the proper size to fit snugly in the sockets 5 and turn freely therein under the action of the turning devices, presently to be explained. A plurality of these.

plate straining and clamping roll sections 7 are mounted in each of the longitudinal sockets or pockets 5 of the printing-cylinder, the

number of the rolls 7 depending upon the length of the printing-cylinder and the required adjustment for the printing-plate.

Each of the clamping and straining roll sections 7 has a longitudinally-extending angular recess or cavity 10 cut in its face, and fitting snugly in this angular cavity is a clamping-bar 11, having a plate-engaging flange 12, which is shaped to fit snugly upon the curved surface of the clamping-roll section for securely clamping the edge of the printing-plate P between it and the roll.

13 13 are threaded bolts passing through openings 14 in the clamping-plate 11 and threaded into sockets 15 of the clamping-roll sections. The bolts 13 are formed with collars 16,whieh engage in the recesses formed in the clamping-plate 11, and the squared heads 17, by which the bolts maybe rotated in their seats.

Adjacent to the sockets or pockets 5 in the plate-cylinder are formed the series of deep recesses or cavities 20 for the purpose of allowin g room for the free movement of the cla1nping-plates 11 when the clamping-roll sections 7 are rotated in their supporting-sockets for straining the printing-plate. These recesses 20 are separated by dividing walls or lugs 21, in which are cut the circular recesses 22.

23 is a worm-gear mounted upon a journalbolt 24:, which is journaled in the bearing 25 and secured in place by a washer 26 and nut 27. The worm-gear 23 rests in the circular socket 22 and is supported in mesh with a segment worm-gear 28, formed in one face of the clamping-roll section 7. The worm-gear 23 is provided with a squared wrench-engaging end 29, by which it may be rotated in its bearing. It will be observed that the rotation of the worm-gear 23 will cause the roll-section 7 to rotate slowly in :its supporting-socket 5.

Each of the roll-sections 7 is provided with a segment worm-gear 28 adjacent to one of its ends, and each of these segment wormgears is in constant mesh with the controlling and operating wormgear 23, so that the several roll-sections 7 may be independently rotated by means of a wrench or suitable key for straining the printing-plate throughout its area.

The roll-sections 7 are mounted end to end in the supporting-socket 5 of the printingcylinder and are held in place by the engagement of the worm-gears The gears 23 fit snugly in their supporting-sockets 22 and are,

held thereby into working engagement with the segment-gears on the clamping-roll sections. The cut-out portions 6 of the sockets 5 are less than half the circumference of the sockets in extent, so that there is no possibility of the sectional clamping-roll sections being forced laterally out of their socket.- The sectional rolls can be removed only through the open ends of the supporting-sockets.

It will be observed that with myimproved plate straining and clamping device the front and rear edges of the plate P are clamped to the sectional rolls at different points by means of the clamping-plates 11. The several sections of the rolls are then rotated in their bearings by the means described until the printing-plate has been properly strained 7 over the plate-supporting surface 2 of the cylinder. As the sections of the clampingroll are rotated for straining the printing plate it will be observed that the plate will be rolled upon the clamping-roll over the beveled or curved edges at of the plate-supporting surface of the cylinder, so that there will not be any abrupt bend or break in the plate. This arrangement also enables the operator to more effective] y strain and stretch the printing-plate over the cylinder by reason of the absence of abrupt edges, over which the plate must be drawn, it being perfectly clear that the plate will yield more readily to the straining action of the straining and clamping rollers than it would to the action of a clamping and straining device which pulls the edge of the plate down over an abrupt edge of the plate-supporting surface. The improved arrangement is therefore more effective in operation and preserves the printing-plates better than other forms of clamping devices. The clamping-rolls are also of great value, because of the small proportion of the cylinder-surface utilized for their reception. WVith my improved clamping devices I am able to utilize a much larger proportion of the cylinder-surface for the reception of the printing-plate than with any other clamping device known to me.

Having thus described my invention, the following is what I claim as new therein and desire to secure by Letters Patent:

1. The combination of a printing-cylinder havinga plate-supporting surface, a plurality of independent plate straining and clamping rolls arranged end to end and journaled in the cylinder adjacent to the edge of the platesupporting surface, independent means upon the several straining and clamping rolls for engaging the edge of the printing-plate, and independent means for rotating each of the rolls in its bearing, substantially as set forth.

2. The combination of a printing-cylinder having a plate-supporting surface'and a rollsupporting socket adjacent to one edge of the plate-supporting surface, with a plate straining and clamping roll journaled in said socket and provided with means for rotating it, and means for clamping the edge of a printingplate to the roll, said roll-supporting socket in the cylinder having a longitudinal opening or cut-out portion of less than half the circumference of the socket so as to inclose more than half the circumference of the roll,- substantially as and for the purpose set forth.

3. The combination of a printing-cylinder having a plate-supporting surface and a rollsupporting socket adjacent to one edge of the plate-supporting surface, a plurality of plate straining and clamping rolls journaled in said socket, each of the said rolls being provided with a segment-gear and with a plate-clamping device, a series of independent operatinggears journaled in the printing-cylinder and supported in mesh with the several segmentgears of the rolls, substantially as set forth.

4. The combination of a printing-cylinder having a plate-supporting surface and a roll- Ito supporting socket adjacent to one edge of the plate-supporting surface, a plurality of plate straining and clamping rolls journaled in said roll-supporting socket, a segment-gear uponeach roll, a plate-clamp mounted upon each roll, recesses or pockets formed in the printing-cylinder adjacent to and parallel with the roll-supporting socket for the reception of the plate-clamps when the rolls are rotated, di-

viding lugs or Walls separatingsaid clamp- 10 

